1. Field
The disclosure relates to methods and devices for adjusting transmit power in wireless communication systems. More particularly, the disclosure relates to a method and device for adjusting transmit power in a real-time, distributive manner to enhance the signal-to-interference plus noise ratio (SINR) of a user equipment (UE) in an inter-cell interference environment.
2. Description of Related Art
In order to meet the demand for wireless data traffic soaring since fourth generation (4G) communication systems came to the market, there have been ongoing efforts to develop enhanced fifth generation (5G) communication systems or pre-5G communication systems. For this reason, 5G communication systems or pre-5G communication system is called the beyond 4G network communication system or post long term evolution (LTE) system.
For higher data transmit rates, 5G communication systems are implemented on ultra high frequency bands millimeter wave (mmWave), such as, e.g., 60 GHz. To mitigate path loss on ultra high frequency bands and to increase the reach of radio waves, the following techniques are taken into account for 5G communication systems, beamforming, massive multi-input multi-output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large scale antennas.
Various technologies for enhancing the network of 5G communication systems are also being developed are, such as evolved or advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving networks, cooperative communication, coordinated multi-point (CoMP), and interference cancellation.
There are also other various schemes under development for 5G systems including, e.g., hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), which are advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA), which are advanced access schemes.
In mobile communication systems, homogeneous base stations generally transmit data in the same transmit power. However, actual data traffic distribution is uneven and varies over time. User equipment (UE), while moving in the mobile communication network, experiences varying radio frequency (RF) characteristics. Therefore, a need exists for enhancing the performance of mobile communication networks by adjusting the transmit power of base stations based on real-time RF distribution and RF state the UE experiences.
Common wireless communication systems adjust transmit power on a long-term basis using statistical information about network loading and measurement information gathered for a predetermined time. However, such long-term transmit power adjustment, although adequate for coverage optimization, is inapplicable when channel state and network loading are varied in real-time as the UE moves.
The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.